Although most eukaryotic cells contain similar parts, these parts are differentially arranged in different cell types. Furthermore, cells are dynamic, rearranging their internal structures in response to the environment and during developmental processes. Cellular architecture is important for cellular function. This application proposes to use S. cerevisiae to examine how cellular organization is established and maintained by studying the complex internal rearrangements that occur during spore morphogenesis, when a single diploid cell is transformed into an ascus containing four haploid spores. The long-term goal is to understand how cells regulate their internal architecture. This research seeks to understand how the structures built during spore development are organized. The proposal focuses on understanding the function of SPO71, which encodes a PH domain-containing protein that is essential for proper spore wall morphogenesis. SPO71 is thought to be important for the organization rather than the production of the spore wall because spore wall components are made in spo71 mutants but fail to localize correctly. The study of SPO71 should yield insights into how spatial organization is established and maintained during sporulation. We will understand how SPO71 contributes to spore morphogenesis by further characterizing the defects seen in cells lacking SPO71 through the use of molecular markers that allow for the visualization of structures inside sporulating yeast cells. Experiments are also proposed to examine the potential role of the Spo71p PH domains and N-terminus in controlling Spo71p function. Finally, this proposal contains experiments designed to identify molecules that work in concert with SPO71 to generate proper spatial organization during spore development. The experiments in this proposal should provide information about the organization of spore morphogenesis and insights into how a developmentally regulated PH domain containing protein is utilized to regulate cellular architecture. PUBLIC HEALTH RELEVANCE: Understanding how cells regulate their internal architecture is important for understanding cellular function. This is important for human health because cells in disease states frequently take on morphologies distinct from healthy cells and these morphological changes frequently underlie pathological diagnosis.